Jerry- Haven't had the pleasure myself, but I've disassembled these types of windows B4. Inside is a Zee-shaped aluminum frame w/a buncha square drive screws. The screws seat into a groove in the aluminum frame of the outer, window assembly. Tightening the screws squeezes the window frame to the outer body skin (with a strip of clay-like sealer tape between aluminum & fiberglass to keep water out), and the Zee to the inner wall. Its all friction.
Best way to find the offending squeak is to have somebody drive the coach around on a Baja highway, or a concrete freeway near you, while you put your hand on every few inches of each section of frame, screen, etc. When you press on the correct place, the rattle will stop. This is officially referred to as the Izzy method. When you "Izzy" the location of the problem, you can tighten screws (unless the trouble is they are stripped, in which case go to Ace Hardware or NAPA and get a stripped screw thread kit & follow directions, or get same head type & length screws but larger diameter), add a shim, or add a felt strip as req'd. If the trouble is inside the wall, say below the window frame it rubs on an aluminum tube, you can remove the Zee ring entirely and install shim, felt, glue, chewing gum, etc., then reinstall the Zee. Take care not to strip screws, which is officially referred to as "wrving" a screw or bolt. (Other manufacturers may use quaint colloquialisms differing from those presented here; these are the official OED elucidations.)
Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project